00:00This is an unprecedented and historic storm we're talking about because this is very unique.
00:06Yesterday Michael Mann addressed storm Hurricane Harvey and the connections with climate change.
00:16On his Facebook page he posted this post, I will read it briefly.
00:20What can we say about the role of climate change in the unprecedented disaster that is unfolding in Houston with
00:25Hurricane Harvey?
00:28There are certain climate change related factors that we can with great confidence say worsened the flooding.
00:37Sea level rise, attributable to climate change, some is due to coastal subsidence due to human disturbance, for example from
00:48oil dwelling, is more than half a foot over the past few decades.
00:54That means that the storm surge was a half foot higher than it would have been just decades ago, meaning
01:01far more flooding and destruction.
01:05In addition to that, sea surface temperature in the region have risen about 0.5 Celsius, close to 1 Fahrenheit,
01:14over the past few decades, from roughly 30 Celsius, 86 Fahrenheit, to 30.5 Celsius, 87 Fahrenheit,
01:25which contributed to the very warm sea surface temperatures, which contributed to the very warm sea surface temperatures, 38.5
01:30to 31 Celsius or 87 to 88 Fahrenheit.
01:34There is a simple thermodynamic relationship known as a simple thermodynamic relationship known as the Clausius-Clapperian equation that tells
01:42us there is roughly a 3% increase in average atmospheric moisture content for each 0.5 Celsius or about
01:521 Fahrenheit of warming.
01:55Sea surface temperature in the region.
01:58Sea surface temperature in the area where Harvey intensified were 0.5 to 1 Celsius warmer than current day average
02:07temperatures, which translates to 1 to 1.5 Celsius warmer than the average temperatures a few decades ago.
02:18That means 3 to 5% more moisture in the atmosphere.
02:23Yes, this is the climate change connection here, which attributed to this event.
02:31The large amount of moisture means the potential for much greater rainfalls and greater flooding.
02:38The combination of coastal flooding and heavy rainfall is responsible for the devastating flooding that Houston is experiencing.
02:45Not only are the surface waters of the Gulf unusually warm right now, but there is a deep layer of
02:52warm water that Harvey was able to feed up in when it intensified at near record pace as it neared
02:59the coast.
03:00Human coast warming is penetrating down into the ocean warming, not just the surface, but creating deeper layers of warm
03:06water in the Gulf and elsewhere.
03:08So, Harvey was almost certainly more intense than it would have been in the absence of human coast warming, which
03:15means stronger winds, more wind damage and a larger storm surge.
03:19As an example of how this works, we have shown that climate change has led to a dramatic increase in
03:25storm surge risk in New York City, making devastating events like Superstorm Sandy more likely.
03:31Here is a link to the study.
03:33I will link this entire post below the video.
03:35Finally, the more tenuous but potentially relevant climate factors.
03:39Part of what has made Harvey such a devastating storm is the way it has stored right near the coast.
03:50Continuing, Pummel Houston and surrounding regions with a seemingly endless deluge which will likely top out at nearly four feet
03:57of rainfall over a several days long period before it's done.
04:01This stalling is due to a very weak prevailing winds which are falling to steer the storm off to sea,
04:06allowing it to spin around and wobble back and forth like a top with no direction.
04:10This pattern in turn is associated with a greatly expanded subtropical high pressure system over much of the US right
04:19now with a jet stream pushed well to the north.
04:24This pattern of subtropical expansion is predicted in model simulations of human caused climate change.
04:32More tenuous but possibly relevant still is the fact that very persistent nearly stationary summer weather patterns of this sort
04:40where weather anomalies both high pressure dry hot regions and low pressure stormy rainy regions stay locked in place for
04:49many days at a time appears to be favored by human caused climate change.
04:58In conclusion, while we cannot say climate change caused Hurricane Harvey that is an ill posed question, we can say
05:05that it exacerbate several characteristics of the storm in a way that greatly increases the risk of damage and loss
05:13of life.
05:15Climate change worsens the impact of Hurricane Harvey.
05:18Climate change worsens the impact of Hurricane Harvey.
05:19So check this out, the link is below the video.
05:22Visit the links.
05:24Read the studies for yourself.
05:26Yes.
05:27And while this is an extraordinary unlucky at odds event with stalling and returning and so forth, this will repeat
05:40itself.
05:41And I would say this kind of event in one form or another will repeat itself with such a dilute
05:47not in 500 years, not in 200 years, yes, maybe in your lifetime, maybe in a decade.
05:57So in addition to this large scale regional increase in extreme flooding, you've got randomness that makes some people experience
06:05a big increase and some people experience no change at all.
06:08So if people have different perceptions about climate change impacts, that's weather mucking with the trends that are going to
06:15make some places be unlucky and some places be lucky.
06:19But eventually those odds will even out over time.
06:21go ahead.
06:21see you at that area.
06:21take it uncon closure to you at the 01.
